Methamphetamine (METH) is a major drug of abuse in the USA and the world. Furthermore, METH abuse by females of child-bearing age has become a significant public health concern in terms of potential short and long-term risks to an exposed fetus. In pregnancy, METH can cross the placenta and reach the fetus. My program is designed to make major advances in our understanding of how the innate immune system of neonates is affected at the molecular and cellular levels by maternal METH abuse. Although there is substantial information on the physical and cognitive defects caused by METH in offspring exposed to the drug during pregnancy there is a dearth of knowledge regarding its impact on innate immunity. I have previously shown that METH alters the capacity of the adult host to effectively respond to microbial challenges and I hypothesize that neonates exposed to METH in utero will have further defects in innate immunity. There are two AIMS proposed: (1) to determine whether offspring exposed to METH during pregnancy have defective innate immunity; and (2) to assess the effect of METH on the integrity of the BBB of exposed neonates in response to microbial challenge. I believe this project is of considerable significance in the fields of immunity, host-pathogen interactions and drug abuse. I anticipate that understanding the relationship between these fields may help to develop more effective public health strategies to deal with this scourge on our society. Methamphetamine is a major scourge on our society. The drug adversely changes people's behavior, including putting users at high risk for the acquisition of diverse infectious diseases. Unfortunately, pregnant women comprise an important population using methamphetamine. There is very little information on the effects of the drug use on the offspring of methamphetamine abusing mothers. Using mouse models of abuse, my program will define the impact of maternal methamphetamine use on the function of specific cells of the innate immune system and the cells that comprise the blood brain barrier of neonates.